The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Memory arrays, such as static random access memory (SRAM) array, and the like, are of wide usages in silicon devices. Transistors in a memory array can have different characteristics than transistors in a regular logic circuit. In an example, in order to achieve high density, layout of the transistors in a memory array can violate regular layout design rules and have different levels of implantation, and thus the transistors in the memory array have different characteristics than transistors in a regular logic circuit that follow the regular design rules.